1. Field of the Invention
The present invention relates to a stationary sliding bar for guidance of a traveling fiber material web, notably a paper or cardboard web.
2. Description of the Related Art
The textbook xe2x80x9cDie Papierfabrikation and ihre Maschinenxe2x80x9d [Paper Manufacture and Its Machines] by F. Mxc3xcller. II. Vol. 1938, page 467, (Sketch No. 300) shows in the area of a rotary slitter a so-called non-slit web spreader, which after longitudinal slitting of the paper web passes the slit webs to a winding system.
EP 0 643 168 A1 discloses in FIGS. 3-6 a plurality of so-called air flotation beams, comprised each of a hollow profile beam which on its side away from the paper web has a plurality of blowing. air orifices. These air flotation beams are normally arranged on the outlet end of a web coater, and at that, on the coated web side. Involving considerable expense to feed blowing air, care is taken that the fresh sized, and thus still moist, side of the paper web in no way makes direct contact with the air flotation beam.
The present invention provides a stationary sliding bar which guides a paper or cardboard web and has a relatively low-cost manufacture and, normally, application without active air supply.
An advantage of these measures is that, for one, the web being guided may temporarily or at times make contact with the surface of the sliding bar, but that the web, on the other hand, slides at sufficiently high speed of travel for the mostxe2x80x94due to the creation of an aerodynamic floatation wedgexe2x80x94across the rounded, convex surface of the sliding bar without touching it. Hence, the inventional sliding bar is suited preferably for use wherever heretofore a rotatable web guide roll was required. Such guide rolls not only are expensive to fabricate, but also require routine maintenance. In contrast, considerable savings are achieved with the present invention.
Compared with conventional guide rolls, the stationary sliding bar according to the present invention has a low weight and no movable elements (no rotating mass), for which reason only a simplified support is needed. An additional major advantage is constituted in that the inventional sliding bar is insensitive to elevated temperature and temperature fluctuations.